Fluid pressure brake



Aug. 27, 1935. c. c. FARMER FLUID PRESSURE BRAKE Filed Nov. 5,-1934 NO \I Am vw \Q @Ql N MIL.

Omv m muv Q Ev INVENTOR CLYDE O. FARM ER ATTORNEY Patented Aug. 27, 1935 Clyde Farmer, Pittsburgh, Pa assignor to The g Westinghouse Air Brake Company, Wilmerding, I

.Pa., a corporation of Pennsylvania .Application No'vem'bcrfi, 1984,*Serial"No.151129? I l 9 Claims. (01. sea-23) This invention relates to fluid pressure brakes and moreparticularly to-a brake controlling valve mechanism which operates. in accordance with variations in brake pipe pressure to control the brakes on a car.

,For controlling the brakes on passenger and other cars particularly adapted'to operate in relatively short trains at high speed, thewell known universal valve is employed, which isprovided with a so called protection valve that is'operative to effect an emergencyreduction in brake pipe pressure and thereby an emergency application of the brakesfin casethe brake pipe pressure falls to a predetermined low degree through leakage or otherwise. 7 1 1 I At times, a carequipped with a universalvalve is hauled in a freight train. In freight service it is often necessary to separate a train, such" as at a gradecrossing or for switching a car out of the train, and 'inorder to facilitate as rapid handling of the train as possible, it is customary,

after effecting a service application of the brakes on the train, to close'the-brake pipe angle cock at the, front of the portion of the train to be temporarily cut, oit'andthereby hold as muchfluid underpressure therein as possible, so that when connected up .to the front portion. of thetrain again a minimum of time-will be required. to recharge the brake system. andrelease the brakes and thus condition the train .for moving.

-In' case a car equipped with the universe valve mm the portion of a train cut off and leakage in thebrake system reduces thebrake pipe pressure to the setting of the protection valve, then the protection-valve operates-to effect an emergency reduction inbrake pipe pressure and thereby an emergency application'of the brakes. Then, before the train can be moved, after coupling the sections of the train together, the brake pipe must be completely recharged and the consequent delay in movement of the train is undesired,

While the above difliculty may -be overcome by eliminating the protection valve, otherdifficulties equally as undesirable will be then encountered,

as will now be explained. b

In the universal valve there is a high pressure valve, which is normally held seated by fluid under pressure from the emergency reservoir acting on one side and which is operative upon venting of fluid under pressure from said sideto' establish a communication through which fluid under pressure is supplied from the emergency reservoir to the brake cylinder. ,This venting of fluid from the high pressure valve occurs in effecting an emergency applicationof the brakes by wayof the release valve porjtioii of' the universal valve, when said portion-is in' application position, and from thence through the emergency valve portion in emergency position.

When a car equipped with a universal valve is in a cut ofi portion of a train, 1eakage {from the brake pipe will act to maintain the service 'portion,;in-cluding the release valve portion, in

application position, in which the high pressure,

valve is connectedfto the seat of theemergency slide valve, sothat emergency reservoir pressure acting to seat the high pressure valve also acts on the seating face of the emergency slide valve and will blow said slideva'l've off" its seat: if brake pipe pressure, and therefore thepressure in the emergency valvecham'be'r acting to hold said slidevalve seated,- becomesrsuificiently reduced due to brake pipe. 1eakage, i. e.,'r educedto apreswould operate. 1 [It the emergencyslidevalveis blow from its seat, it willpermit' foreignmatter to get on-said sure lower than that at which the protection-valve seat andlater'cause the emergenpyvalvei device to "fail, it may also permit sucha reduction in pressure on' the high'pressure valve as to permit itfto'operate to'connect the emergency reservoir to thebrake cylinder, and further, itfmay permit ,suflicient flow of 'fluidfrom the emergency valve chamber to effect operation of a brakepipe vent valve device, which forms-a part offthe universal valve, to initiate an emergency reduction in brake pipe pressure'on the cut off portion of the train, all of which operations are undesirahle.-

The principal object of 'the invention is to proa vide an improved universal valve adapted topperate-in theiusual manner when employed in passenger or othersuch short train, high speed service, and which is also adapted. t operate in ireight service without encountering anyfofzthe above described difficulties] 7 ,7 1 Theobjectis accomplishedby providing a new, so called,,high pressure cap 'forjthe emergency portion of the universal-valve, jrom' which high pressure cap a. device, including a protection valve,"'may be remove'dand. another device, in-

cluding a'jpilot valve device, maybe applieddn its" placejso as to condition the'universalivalve for use infreightse'rvic'e.

' By'the use 'ofthe pilot valve devicegtheemer- ,gency slide ,valve is neversubiected to ith'e pressure of fiuidlwhich acts to'normallyhold the high pressure valvejseated; instead,jan riddl tioiial valve is'pi'ovidedfor' venting'flui'dwhich and consequently the pressure in the emergency 7 acts to hold the high pressure valve seated, said additional valve being adapted to be unseated by fluid under pressure supplied from the emergency valve chamber when the emergency valve device operates to effect an emergency application of the brakes. By this construction, the protection valve may be dispensed with when a universal valve is to be employed in freight service and the emergency slide valve will not be blown from itsseat even thoughthe brake pipe pressure,

valve chamber, should reduce to atmospheric pressure due'to brake pipe leakage.

It has heretofore been proposed to employ a pilot valve devicecontrolled by an emergency valve device for controlling the operation of a high pressure valve, but according to the present invention, there is provided a new high pressure cap for the well known universal valve, such that the protection valve may be. employed, or the pilot'valve devicem'ay be employed according to the service in which the universal valve is tobe operated. V, 7

In the accompanyingdrawing,Fig. 1 is a diagrammatic view, mainly. in section, of a fluid pressure brake equipment including a universal valve embodying my invention and showing therdevice applied forconditioning said universal valve for passenger; service or the like; .and Fig. 2-is a diagrammaticview or a portion of the universal valve shown in Fig. 1, and showing the device applied for conditioning the universal valve-for use in freightservice.

'- ;As shown in -the drawing, the fluid pressure brake equipment ,comprisesa universalvalve, with which is associated the usual auxiliary reservoir l, service reservoir 2, emergency reservoir 3. and brake cylinder 4. 7

The universal valve comprises a pipe bracket 5, to which theseveral reservoirs and thejbrake cylinder are connected and also to which the usual brake pipe 6 is connected; Mountedlon one face: of the bracket is the usual serviceapplication portion which comprises an. equalizing valve device I and a releasevalve device 8' which device in the drawing .is shown in the usual application position,. while mounted on another .face of the bracket 5 is af'quick action-portion which includes an emergency'valve device 9, and a brake pipe'vent valve device Ill and high pressure cap ll carried by said emergency valve device,- a

The equalizing valve device 1 and the universal valveis adaptedto, operate upon a service reduction in pressure in brake pipe 6 to effect a service application of the brakes and upon an increase in brake pipe pressure to efiecta release of the brakes, thereleaseof the brakes being controlled by therelease'valve device 8 which is positioned in accordance with the operation of the equalizing valve portion 1. 3

The release valve device 8 is shown in a position which would be assumedin a cut off portionof .'a train after having effected a service application of the "brakes, said release, valve device compris ing twof spaced pistons l2 and I3 connected, by astem l4 .and a slide valve l5 disposed in a chamber I6 formed between said pistons and adapted tov be moved by said pistons, thechambe'r I6 being in constant communication withthe emergency reservoir 3.through passages lfland l8, and'pipe l9, l

, The emergency 'valvedevice 9 comprises a piston- 20 having atfone side'ja chamb r, 2| adapted at the opposite side a valve chamber 22 connected to a quick action chamber 23 through a passage 24 and containing a main slide valve 25 and an auxiliary slide valve 95 .adapted to be sage 28 to a passage 29, through which passages fluid under pressure is adapted to be supplied to the brake cylinder 4 in the usual manner, the intercepting valve device 21 being provided to control the flow of fluid under, pressure to passage '28, first from the service reservoir 2 and then from, the emergency reservoir 3, in the usual manner.

The high pressure valve piston 26 has at one side a chamber 30 which contains, a spring 3| adapted to urge saidvalve piston into engagement with a seat rib 32, provided in .the casing, for closing communication from passage 28 to passage 29. The chamber 30 is connectedby a L passage 33 to the seat of the release valve slide valve I 5. When the release valve slide valve in the lower or release position, a port 34 therein registers with passage 33, which permits fluid under pressure to flow from valve chamher. It, and thereby the emergency reservoir 3, to chamber 30 and therein act with spring 3|. to hold the high pressure valve piston 26 seated on seat rib 32 against the opposing pressure of fluid from the emergency reservoir 3 acting on the opposite side of said valvepiston outside of seat rib 32, the emergency reservoir 3 communicating with said valve piston through pipe l9, passage 18, passage 35, a cavity 36 in the intercepting valve'device Z'Iand passage 28. When the re-'- lease slide valve 15 is in the application position, aslshown in the drawing, passage 33 from the high pressure'valve piston chamber 3ll is con nected through a cavity3l in said slide valve to a passage 38, which leads to a gasket face 39 provided'on the high pressure cap ll.

According to the invention, a device 40, adapted. to. condition thejuniversal valve for operation in passenger train service, is mounted on the high pressure cap ll against a gasket 4| disposed on the gasket'face 39, as shown in Fig. 1 of the drawing, the devices!) having a cavity 42 adapted to establish communication between passage 38 from the'spring side of the high pressure valve 26 to a passage 43 which leads to the seating face of z the main emergency Slide valve 25, so that the for closing communication from' a passage 29,

leadingto brake pipe 6, to a passage 58 which is in constant communication with the emergency piston chamber 2i through a strainer device El, passage'52,through a restricted port in a choke plug and passage 54. A check valve 55 disposed in a passag'eBEi bypassing choke plug 53, said check valve and choke being associated with the protection valve piston M in the device 4-0 to provide standard operaticn of the universal valve in passenger service or the like.

L'Ihe passage" leadsto the .topor. the protection valve piston L44-and is. adapted: to be opened to chamber when theprotection valvepiston 44 is in engagement with seat rib '48, said passage atthe top of the protection'valvabeing con nected to a passage 51 which leads to a .passage 58 in the .high pressure cap and from thence through a strainer 59 to the usual charging'pas sage 60 in the casing of the emergencyvalve device 9. v c

In operation, when the brake system is charged with fluid under pressure,'fluid under. pressure from .the brake pipe 6 acts in the emergency valve pistonchamber 2|, being connected thereto through passage 49, past .the protection valve piston 44, whichvis held in its upper position by the pressure: of fluid supplied through passage 49, and from thence through .passage59, strainer 5i, passage 52, choke plugi53 and passage 54,-while the emergency valve chamber22 and quick ac-. tion chamber 23 are also charged with fluid under pressure from-the brakepipe 6 by way of passages 50, 51. and. 58, through strainer 59, passage 69,.past a checkvalve 6|, through passage 62, port163 inthe emergency slide valve 25 and port 64 in the auxiliary slide valve 95.

The reservoirs I, 2 andj'3are charged with fluid under pressure in the usual manner, fluid from the emergency. reservoir being supplied through port 34 inthe release valve'slide valve l5 to passage 33 leading-to chamber 30 beneath the, high pressure valve v piston 26, when the release valve slide valve [5 is inthe lower or release position. The pressure of fluid thus supplied to chamber 30 acts .inconjunction with spring 3| to hold the .valve piston 26 seated :onrseat rib 32 against emergency reservoir'pressure, acting onrthe opposite side of. said valve pistonoutside of-saidseat rib, as supplied through pipe l9, passages 18 and 35,;cavity in theintercepting valvedevice '21 and passage 28.

If it is desired to efiect an. emergency application of:-the brakes, a sudden emergency reduction in pressure is effected in the brake pipe 6, which causes theequalizingflyalve1device land release valve device-8 to operatein the usualmanner, the

release valve slide'valve 15 being shifted to its upper orappllcation position, as shown in Fig. .1 of the drawing, inuwhich position chamber 39, at the lower side of, thehigh pressure valve piston 26, is connected to the seat of the emergency slide valve 25 by way-oi passage 33, cavity3'l in slide valve l5, passage 38, cavity 42 in device and passage 43, the passage 43 being-normally lapped by the emergency slide valve 25. I

When. anemergencyreduction in brake pipe pressure is effected, a corresponding reduction in pressure occurs in'the emergency piston chamber 2 l past the check valve55, which permits the pressure of fluid in the emergency valve chamber 22 to shift the emergency piston 20, and thereby the ;slide-valves..2,5 and 95 outwardly, toemergency; position, in which a cavity 65' in the slide valve .25 connects passage-.43 from chamber 30 atathe spring side ofthe high pressure valve piston-26 to a passage 66 :which leads to; an atmospheric vent passage 61. Fluid under pressure is thereby vented from chamber 30 at the lower side of the high pressure valve piston 26,.which permits emergency reservoir pressure acting on the opposite side to move said-valve piston out of. em gagement with seat rib 32vand thereby establish the usual communication betweenpassages '29 and. 29, through. which fluid under pressure is adapted to. be supplied from the service reservoir;

2 andemergency reservoir 3. to the brake cylinder.

In: emergency positiontiof the main slide'valve 25, a port 68in said slide valve registerswith. a

passage. 69which' leads to the side of the high pressure valve piston 25, within the seat rib 32, towhich'passage 29 is also connected, so that as fluidunder pressure is supplied tothe brake cylinder throughpassageaZS, fluid at the same pressure also flows into the emergency valve chamber .22 and thereby insures that the emergency valve device will remain in emergency position and also acts to maintain the emergency slide valve 25 seated;

I If, instead of effectingan emergency application of the brakes by initiating the sudden reduce tion in pressure in brake pipe 6 in the usual manner, the brake pipe pressure becomes reduceddue to leakage to suchadegree that spring .41, acting on the protection valve piston 44, is enabled to overcome the opposing brake pipe pressure, then said spring moves said valve piston toward the seat rib 43 and thereby establishes the commu:

nication between passage 59 and chamber which isopen to the atmosphere through. passage 46, and through this communication fluid under pressure'is suddenly vented from theemer:

gency valve piston chamber 2| by wayof check valve 55, thereby causing operation of the emergency valve device ,9 and high pressure valve piston 25 in the same manner ashereinbefore described...

.Ifthe pressure in the emergency piston chamher 2! should be reduced by l-eakagefrom the brake pipe, it willbe noted that the pressure in valvechamber 22 may, in case of leakage past the 2 emergency piston 29,reduceas the brake pipe pressure reduces, or if the leakage past piston 29 is not great enough to reduce the pressure in chamber 22 as rapidly as brake pipe pressure is reduced, a differential of pressures'will be ob tained on said piston to move it towards the'usual serviceposition until a sufficientregistration be tween port 9! in the auxiliary slide valve 95. and port .88. in the main slide valve. 25 is obtained to permit the pressure in saidchamber to reduce, by flow through said ports and the-atmospheric exhaust port-61, at the same ratev as brake pipe pressure is being reduced. However when the pressure in the brake pipe, and consequently that in the emergency valve chamber .;22,. becomes reduced to the setting of the protection valve 44,

. said protection valve will operate to efiect an emergency reduction in-brake pipe pressure and thereby cause the emergency valve device 9 to operate as abovedescribed, Theabove operation of the .Lmiversal valve with the valve device 49 applied to the high pressure cap H, is the usual ,or standard operation which ,is desired for use in, controlling passenger or other relativelyshort; high speed trains, it being noted that the:protection valve 44 acts in the usual manner; to -protect against brake .pipe 5 pipe pressure becoming reduced, due to leakage-or otherwise, to, such ;a

degree that an efiectivezapplication of the brakes 1 cannot be obtained, and; with tl'iis-., constructionthe pressure. ofrfluicl acting inchamber fillto hold the high pressure-valve piston 26 seated, is permitted; to act on T' the seating facef of the main slide valve 25 without danger of blowing said slide valvefromj its seat, since'the pressure in the emergency valve chamber 22- cannot become reduced, dueto leakage or otherwise, toa degree lower than that-at which the protection valve-44 operatesto vent ,thebrake pipe, since;-in emergencyposition of the emergency slide valve 25 the valve chamber 22 is chargedtobrake cylinder pressure, as hereinbefore described.

If it is desired to operate the universal-valve in freight servicein which it-is not desired to use the protection valve 44, then the device 46' is removed fromthe high pressurecap II and device .10 is applied in itsrplace, Fig. 2 of the drawing; 1

The device 78 is provided with a passage 72 which includes astrainer 13 and which establishes direct communication from the brake pipe passage 49 to passage II that leads to the emergency, piston chamber 2!, it being noted that the choke plug .53 and check valve .55 provided in the device 40 in Fig. 1, are not provided in the device 10, since said choke plug and check valve arerequired only where the protection valve is employed;

as shown in The device 'lOis also provided with a passage 14 connected to passage 12 and leading to passage 58 in the high pressure cap H, through which communication" the emergency valve chamber 22 and quick action chamber 23 are adapted to be charged with fluid under pressure from the brake pipe as will be evident. The device includes a pilot valve 75 contained in a chamber 16 which isconnec'ted by a passage H to passage 38 in'the high pressure cap II, the passage 38 leading to chamber 30 at the spring side of the high pressure valve.

The passage 43, to whichpassage 38 is connected in the device 40, is lapped by the device 10; so it will be evident that the pressure inchamber 30 acting to seat the high pressure valve 26, will not act on the seating face of the emergency slide valve 25, as'is thecaseiin the construction showninFig.1.-.

A spring ,18 is disposed in chamber 16 and acts to urge the pilot valve into engagement with a seat rib '19 which surrounds a bore in the casing through which the fluted stem 8110f the'pilot valve extends.

Apiston 8| is provided with a stem 82 adapted to engage the pilot valve stem 8%),said piston having at one side a chamber 84 and at the opposite side a chamber 85 in constant communication with the atmosphere through a port 96 and an atmospheric chamber- 83.- Thechamber 84 is connected to a passage'flfi which-leads toa passage 81 in the high'pressure cap H and extends through'said high pressure cap to the seat ofthe emergency slide valve 25, it being noted that when the device 40 is applied to the'high pressure cap I l the passageBl is lapped by said device.

The operation of the universal valve with the device 10 applied to the high pressure cap I l is as follows: 1 v When the brake system is charged with fluid under pressure and the devices are in theirnormal'or releasepositions, the pilot valve piston chamber 84 is vented to the atmosphere through passages 86 and 8'|,'a'cavity 88 in the emergency slide valve 25 and the "atmospheric passage 61,

and when in effecting an applicationof the brakes, due to either a service reduction'in brake pipe pressure or;a reduction caused by brake pipe leakage, .the release valve slide valve I5 is inthe position shown in Fig. 1,-the chamber 30 at the lower side of the high pressure valve 26 is connected to the pilot valve chamber 75 through passage 33', cavity 37 inthe release valve slide valve l5 and. passages" 38 and TI.

In efiecting'an emergency application of the brakes, the emergency piston andslide valves and 95 move'toemergency' position in which a port 9ll inthe slide valve 25rregisters with passage 81, which permits fluid underv pressure to flow ,from' the emergency valve chamber 22 throughport 90 and; passages 81 and 86 to the pilot valve piston chamber 84. i

The pressure of fluid thus supplied to chamber 84 actuates the pilot valve piston 8| to unseat the pilot valve 15, which vents. fluid under pressure from chamber at the spring side of the high pressure valve piston 26 by way of passage 33, cavity 31 in the release valve slide valve [5, passages '38 and TI, pilot valve chamber 16, past thepilotvalve l5 and stem 80,.and from thence to the atmosphere through .the' atmospheric chamber. 83. -Upon thus :venting ,fluid under pressure from chamber 30, the high pressure valve piston 26 is operated to-open the comemergency valve chamber 22,- reduces to a low degree due to brake pipe leakage when the protection valve 44 is not employed and'the device 76 is applied, as shown in Fig. 2.

It will now be noted, thatthe universal valve construction employing the device 40, as shown in Fig, l'of-the drawing, provides for standard operationfor passenger'or other relatively short high speed 'service, whilewith th'edevice 10 em--' ployed in place of the device 40', the universal valve-is conditioned for operation in freight service. 1

Since the operation of theuniversal valve is so well known, the above description of the operation thereof has been limitedtoonly those parts which it is deemed necessary to a full'and complete understanding of the invention.

While one-illustrative embodiment of my invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the'terms of the appended claims.

Havingnowdescrib'ed my invention, what I claim as new and desire to secure by Letters Patent, is:

1. Ina fluid pressure brake, in combination, a

brake pipe, a casing containing" an emergency valve device operable upon a reduction in brake under pressure for reducing the fluid'pressure on said high pressure controlling valve device.

2. In' afiuid pressure brake, in combination, a brake pipe, -a casing containing-an emergency valve device operable upon a'reduction in brake pipe pressure for effecting an emergency application of the brakes" and including a slide valve, said casing. having a passagelea'ding-fto the seat 7 of theslide valve; a high pressure" controlling valve deviceb-perable'upona reduction in fluid: with a brake pipe and a:casing,:of'valvei'means:

pressure effected through said passage upon movement of saidslide valve, a removable momber applied to said casing'for blanking sai'dpassage, and means 'in'said member includinga valve j operable to reduce the fluid pressure onsa'id 'high pressure controlling valve device, and -a piston operated by" fluid under pressure upon movement of said slide valve for effecting the operation of said valve.

3. In a fluid pressure brake, in combination, a brake pipe, a casing containing an emergency valve device operable upon a reduction in brake pipe pressure for effecting an emergency application of the brakes and including a'slide valve, said casing having a passage leading to the seat of the slide valve, a high pressure controlling valve device operable upon a reduction in fluid pressure effected through said passage upon movement of said slide valve, a removable member applied to said casing for blanking said passage,

' and for establishing a direct communication between said brake pipe and emergency valve device, and other means in said member operable by fluid under pressure supplied by said emergency valve device for reducing the fluid pressure on said high pressure controlling valve device when said emergency valve device is operated upon a reduction in brake pipe pressure,

4. In a fluid pressure brake, in combination, a brake pipe, a casing containing an emergency valve device operable upon a reduction in pressure for effecting an emergency application of the brakes and including a slide valve, said casing having a passage leading to the seat of said slide valve and normally lapped by said slide valve, a H

high pressure controlling valve device operable upon a reduction in fluid pressure effected through said passage upon movement of said slide valve, a removablemember applied to said casing for establishing communication from said high pressure controlling valve device to said passage, and means in said member operable when the pressure in said brake pipe is less than a chosen degree to effect said reduction in pressure on said emergency valve device;

5. In a fluid pressure brake, in combination, a brake pipe, a casing containing an emergency valve device operable upon a reduction in pressure for effecting an emergency application of the brakes and including a slide valve, said casing having a passage leading to the seat of said slide valve and normally lapped by said slide valve, a high pressure controlling valve device operable upon a reduction in fluid pressure efiected through said passage upon movement of said slide valve, a removable member applied to said casing forestablishing one communication from said high pressure controlling valve device to said passage and another communication between said brake pipe and emergency valve device, means in the last mentioned communication for restricting flow of fluid in the direction from the brake pipe to said emergency valve device and disposed-in said casing operative upona reduce: I tion in fluid pressure'to': establish-a communica tion through which an iapplication'of the brakes is adaptedto be effected, a valve operative upon a reduction: in brake pipe pressure for effecting a reductiontin pressure? on said valve means, ademunication to said valve means, said other device comprising fluid pressure actuated means for opening the last mentioned communication to the atmosphere, said valve beingoperative upon a reduction in brake pipe pressure for supplying fluid under pressure for effecting the operation of said fluid pressure actuated means.

7. In a fluid pressure brake, the combination with a brake pipe and a casing, of valve means disposed in said casing operative upon a reduction in fluid pressure to establish a communication through which an application ofthe brakes is adapted tobe efife'cted, a valve movable upon a reduction in brake pipe pressure to a position for effecting the operation of said valve means, a device adapted to be removably mounted on said casing for establishing a communication from said valve means to said valve, said valve in said position opening the last mentioned communication to the atmosphere for effecting the reduction in fluid pressure on said valve means, and another device adapted to be removably mounted on said casing in place of the first mentioned device and adapted to close the communication from said valve means to said valveQsaid other tion in fluid pressure to effect an application of brakes, a valve controlled by the opposing pressures of fluid in the brake pipe and a chamber and movable by the pressure of fluid in said chamber upon a reduction in brake pipe pressure.

to a position for establishing a communication from said valve means through which said ,re-

' duction in fluid pressure on said valve means is adapted to be efiected, a device adapted to be said communication and for establishing another communication to said valve means, and fluid pressure actuated means in said device operative to effect a reduction in pressure on said valve 7 7 means through the last mentioned communication, said valve beingoperative in said position to supply fluid under pressure from said chamber to said fluid pressure actuated means for effecting the operation thereof.

9. In a fluid pressure brake, the combination with a brake pipe, of an emergency valve device controlled by the opposing pressures of the brake I pipe and a valve chamber and movable to an emergency position upon a reduction inbrake pipe pressure,,a cap adapted to be carried by said dispbsed in said'cap and operative upon a re:

duction inJfiuid pressure to effect-an application of the brakes, a device adapted to be remo vably applied to said cap for conditioning the emergency valve device in emergency position for reducing the fluidpressure on said high pressure valve; and another device adapted to be removemergencywalve "deviceya high pressure 'valve" 

